MFC(DLL)用ADO远程连接SQL问题
我在OnOK()函数中加入以下代码：
_variant_t var;
::CoInitialize(NULL);//初始化Com库
m_pConnection.CreateInstance(__uuidof(Connection));//初始化Connection指针
m_pRecordset.CreateInstance(__uuidof(Recordset));//初始化Recordset指针
try
{
//打开远程的SQL库
CString sql= "provider=SQLOLEDB;Data Source=218.196.123.36;User ID=sa;Password= '123456 ' ";//数据库访问模式定义为标准的，密码定为123456
m_pConnection-> Open(_bstr_t(sql), " ", " ",adModeUnknown);
}
catch(_com_error e) //捕捉异常
{
//显示错误信息
AfxMessageBox(e.ErrorMessage());
}
try
{
// 创建Recordset对象，执行SQL命令并取得结果记录集；
m_pRecordset.CreateInstance( "ADODB.Recordset ");
m_pRecordset-> Open( "SELECT * FROM chezhou1 ",
m_pConnection.GetInterfacePtr(),
adOpenStatic,
adLockOptimistic,//乐观锁定方式，只有在你调用Update方法时才锁定 记录，在此之前仍然可以做数据的更新、插入、删除等动作。
adCmdText);//表明CommandText是文本命令
while(!m_pRecordset-> adoEOF)//遍历所有记录
{
var = m_pRecordset-> GetCollect(long(0));
if(var.vt!=VT_NULL)
id=var.iVal;
if(id==m_x.GetCurSel())
{// 读入库中的相应字段
var=m_pRecordset-> GetCollect(long(2));
if(var.vt!=VT_NULL)
d1=var;
var=m_pRecordset-> GetCollect(long(3));
if(var.vt!=VT_NULL)
d2=var;
var=m_pRecordset-> GetCollect(long(4));
if(var.vt!=VT_NULL)
d4=var;
var=m_pRecordset-> GetCollect(long(5));
if(var.vt!=VT_NULL)
d5=var;
var=m_pRecordset-> GetCollect(long(6));
if(var.vt!=VT_NULL)
L1=var;
var=m_pRecordset-> GetCollect(long(7));
if(var.vt!=VT_NULL)
L3=var;
var=m_pRecordset-> GetCollect(long(8));
if(var.vt!=VT_NULL)
Lw=var;
break;
}
m_pRecordset-> MoveNext();
}
}
catch(_com_error e) //捕捉异常
{
//显示错误信息
AfxMessageBox(e.ErrorMessage());
}
m_pRecordset-> Close(); //注意！！！不要多次关闭！！！！否则会出错
m_pConnection-> Close();
m_pRecordset=NULL;
m_pConnection=NULL;
::CoUninitialize();//释放程序占用的COM资源

都整了一周了～～
不管是远程还是本地都连接不上～
那位高手指点一下～～
最好给个实例～谢谢～～～
我的邮箱dj_zone@163.com


[解决办法]
vc连数据库的确是很麻烦，我也是看了很多资料才搞懂
给你段c代码，你自己揣摩下
/*******************************************************************
利用ADO访问MS SQL2000
要求: 【1】输出stu_info表内的每一条记录
【2】添加一条新记录
【3】删除名字为 "本拉登 "的记录
*/
#import "c:\Program Files\Common Files\System\ADO\msado15.dll " \
no_namespace rename( "EOF ", "EndOfFile ")
#include <iostream>
#include <iomanip> //for setw()
using namespace std;
class STU
{
public:
char snum[10];
char sname[10];
char ssex[2];

long sage;
char smajor[20];
public:
STU(){}
~STU(){}
};

int main()
{
STU student;
::CoInitialize(NULL);
_RecordsetPtr m_pRecordset( "ADODB.Recordset ");
_ConnectionPtr m_pConnection( "ADODB.Connection ");
_bstr_t bstrSQL( "select * from stu_info ");
char * query_cmd = "DELETE FROM stu_info WHERE sname = '本拉登 ' ";
try
{
m_pConnection.CreateInstance( "ADODB.Connection ");
_bstr_t strConnect= "Provider=SQLOLEDB;Server=(local);Database=student; uid=sa; pwd=sa; ";
m_pConnection-> Open(strConnect, " ", " ",adModeUnknown);
if(m_pConnection==NULL)
cerr < < "Lind data ERROR!\n ";
m_pRecordset.CreateInstance(_uuidof(Recordset));
m_pRecordset-> Open(bstrSQL,m_pConnection.GetInterfacePtr(),
adOpenDynamic,adLockOptimistic,adCmdText);

_variant_t vsnum,vsname,vsage,vssex,vsmajor;
cout < < "学号 姓名 年龄 姓别 专业 ";
cout < < "\n----------------------------\n ";
while(!m_pRecordset-> EndOfFile)
{
vsnum = m_pRecordset-> GetCollect(_variant_t((long)0));
vsname = m_pRecordset-> GetCollect( "sname ");
vsage = m_pRecordset-> GetCollect( "sage ");
vssex = m_pRecordset-> GetCollect( "ssex ");
vsmajor = m_pRecordset-> GetCollect( "smajor ");
if (vsnum.vt != VT_NULL && vsname.vt != VT_NULL && vsage.vt != VT_NULL
&& vssex.vt != VT_NULL && vsmajor.vt != VT_NULL)
{
cout.setf(ios::left);
cout < < setw(14) < < (char*)(_bstr_t)vsnum;
cout < < setw(14) < < (char*)(_bstr_t)vsname;
cout < <setw(8) < < vsage.lVal;
cout < < setw(8) < < (char*)(_bstr_t)vssex;
cout < <setw(20) < < (char*)(_bstr_t)vsmajor;
cout.unsetf(ios::left);
cout < < endl;
}
m_pRecordset-> MoveNext();
}
cout < < "\n----------------------------\n ";
cout < < "\n请输入你要添加的学生信息\n ";
cout < < "学号: ";
cin > > student.snum;
cout < < "\n姓名: ";
cin > > student.sname;
cout < < "\n年龄: ";
cin > > student.sage;
cout < < "\n姓别: ";
cin > > student.ssex;
cout < < "\n专业: ";
cin > > student.smajor;
m_pRecordset-> MoveFirst();
m_pRecordset-> AddNew();
m_pRecordset-> PutCollect( "snum ",_variant_t(student.snum));
m_pRecordset-> PutCollect( "sname ",_variant_t(student.sname));
m_pRecordset-> PutCollect( "sage ",_variant_t(student.sage));
m_pRecordset-> PutCollect( "ssex ",_variant_t(student.ssex));
m_pRecordset-> PutCollect( "smajor ",_variant_t(student.smajor));
m_pRecordset-> Update();
m_pConnection-> Execute(query_cmd,NULL,1);
m_pRecordset-> Close();
}
catch(_com_error e)
{
cerr < < "\nERROR: " < < (char*)e.Description();
}
if(m_pConnection-> State)
m_pConnection-> Close();
::CoUninitialize();
return 0;
}

[解决办法]
可以在对话框中添加一个数据库的控件,在那个控件内连接数据库,然后把测试成功的字符串替换CString sql= "provider=SQLOLEDB;Data Source=218.196.123.36;User ID=sa;Password= '123456 ' ";//,或许可以,我以前遇到的问题就是这样解决的